Acids and bases

Question 1

Properties of acids

Answer 1

Turn blue litmus paper and universal indicator red, Good electrolytes (strong acids are the best), Corrosive and taste sour, React with reactive metals (redox reaction), React with carbonates, hydrogencarbonates, metal oxides and metal hydroxides (neutralisation reaction)

Question 2

Properties of bases

Answer 2

Turn red litmus paper and universal indicator blue, Good electrolytes, Caustic and taste bitter, React with acids and ammonium salts (neutralisation reaction)

Question 3

Davy theory

Answer 3

First theory created that is no longer used, Stated that acids are substances that contain replaceable hydrogens (hydrogens that could be partly or totally replaced by metals) which was incorrect and only applied in redox reactions, not acid-base reactions, States that bases were substances that reaction with acids to form salts and water which is correct

Question 4

Arrhenius theory

Answer 4

Not used to explain in year 12, Stated that acids release hydrogen ions in solution, States that bases release hydroxide ions in solution, Theory was restricted as not all acids and bases are in solutions

Question 5

Bronsted-Lowry theory

Answer 5

Stated that acids are proton donors and bases are proton acceptors, In an equation and acid becomes a conjugate base and a base becomes conjugate acid, H3O+ is formed easily as water has an uneven charge distribution meaning the H+ ion is attracted to the lone pair of electrons in H20

Question 6

Ionisation

Answer 6

when a molecule reacts to form ions (no ions exist before the reaction)

Question 7

Dissociation

Answer 7

when an ionic compound dissolves and releases ions (ions already exist)

Question 8

Strong acids

Answer 8

Fully ionise, Represented by a single arrow as reaction goes to completion, Strength is described in terms of the position of equilibrium, HCl, HNO3, H2SO4, HClO4, HBr, HI (unless stated all other acids are assumed weak)

Question 9

Weak acids

Answer 9

Partially ionise (small Ka, usually less than 1), Represented by a double arrow as reaction doesn’t go to completion, CH3COOH, H3PO4, H2CO3

Question 10

Strong bases

Answer 10

Dissociate in water releasing OH-, Represented by a single arrow, Oxides and group 1 and 2 hydroxides

Question 11

Weak bases

Answer 11

Ionise in water (react to form OH-), Represented by a double arrow, NH3, CO3 2-, HCO3-

Question 12

Strength

Answer 12

Degree of ionisation

Question 13

Concentration

Answer 13

How much solute is present

Question 14

Monoprotic acid

Answer 14

1 mol releases 1 mol of H+ when reacted with a strong base, HCl, HNO3, CH3COOH

Question 15

Diprotic acid

Answer 15

1 mol releases 2 mols of H+ when reacted with a strong base, H2SO4, H2CO3

Question 16

Triprotic acid

Answer 16

1 mol releases 3 mols of H+ when reacted with a strong base, H3PO4

Question 17

Monoprotic base

Answer 17

1 mole can accept 1 mol of H+ when reacted with a strong acid, NaOH

Question 18

Diprotic base

Answer 18

1 mole can accept 2 mols of H+ when reacted with a strong acid, CO3 2-, Mg(OH)2

Question 19

Triprotic base

Answer 19

1 mole can accept 3 mols of H+ when reacted with a strong acid, PO4 3-, Al(OH)3